Magnetic field sensors are known in the art. Today's microelectronic magnetic sensors are typically made in silicon technology, since this allows for cost-effective, miniaturized and complex integration of advanced analog and digital circuitry.
However, Hall devices as magnetic sensor do not show high sensitivity if made in silicon. This is caused by the relatively low mobility of electrons, reaching as maximum about 1500 cm2/Vs at room temperature.
In order to satisfy the requirements of sensing tasks which are either working with very low field (e.g. a compass sensor) or very high speed (e.g. an electrical current sensor capable of sensing a high frequency field), the sensor device itself needs to be made in a different technology with different material, e.g. GaAs, InSb, magnetoresistive, quantum well or other.
Existing solutions using such materials are either discrete combinations of the sensing device and the integrated electronics which are assembled side-by-side on a carrier plate, e.g. the leadframe of a plastic package and which are then interconnected by wire bonding or they are implemented as multilayer structures grown on top of a substrate. While addressing the issue of sensitivity and/or speed, these structures are subject to mechanical stress due to the different coefficients of thermal expansion leading to reliability problems and to degraded sensor performance. Furthermore, such devices are typically much more expensive than magnetic sensors made from silicon.